1. Field of the Invention
The present invention relates to an apparatus for enhancing the performance of a sprinkler assembly or the like, and more particularly to such an apparatus that is relatively inexpensive to construct and maintain, and which includes a frame having a plunger sealably engageable with a spring-biased sleeve which mounts a sprinkler head, the plunger selectively occluding the spring-biased sleeve during movement of the sleeve to a deployed position but being urged to a non-occluding position to release fluid to the sprinkler head when the sprinkler head has reached a predetermined deployed position.
2. Description of the Prior Art
Rotary pop-up sprinklers of various configurations, capacities, and other operational characteristics have been known and utilized for many years. In its most common form, the sprinkler is mounted internally of a casing which is buried in the earth. The sprinkler mounts a lid which is adapted to seal the casing, and provides a supporting surface which enables individuals to cut the surrounding lawn, walk over the device, and generally use the lawn in an unrestricted manner. When the sprinkler is in use, the sprinkler is urged upwardly above the surface of the ground, by water pressure, to permit ejection of the water onto the surrounding areas in accordance with the predetermined irrigation pattern of the sprinkler.
While it is well understood that the utilization of these prior art sprinkler assemblies achieves numerous laudable results, the devices, however, suffer from a multiplicity of common drawbacks which have detracted from their usefulness. For example, nearly all the prior art devices employ, in one form or another, a spring-biased sleeve which mounts a sprinkler head. The spring-biased sleeve is urged, under fluid pressure, to move from a position of rest inside the casing to a deployed position wherein the sprinkler head is positioned in a predetermined attitude above the surface of the earth. While this arrangement usually works with some degree of success, the prior art devices have a common shortcoming in that they frequently do not deploy to a fully extended position because the spring-biased sleeve becomes partially inoperative after it is exposed for prolonged periods of time to dirt or other debris.
Furthermore, the devices frequently do not positively retract substantially internally of their casings when irrigation operations cease. This is due in part to the previously described problem of contamination interfering with the spring-biased sleeve, and it is also due in part to the presence of a weak or old retraction spring which may not cause the sprinkler to retract positively back into the casing. It should be appreciated, of course, that the retraction spring must have sufficient strength to urge the sprinkler back to the position of rest inside the casing, but must also be weak enough such that it can be placed into compression by the water pressure utilized in the sprinkler system. The failure of the sprinkler to retract positively into the casing can produce undesirable results such as being struck and damaged by lawn mowers and the like. Similarly, they may constitute a hazard to people passing through the area in that people may trip over them, or fall into them.
Still another significant problem associated with the prior art assemblies results from characteristics inherent in their design. Prior art devices begin expelling water as soon as water pressure is applied to the sprinkler system, that is, the sprinkler heads begin delivering water even before the sprinkler head is out of the casing and deployed in a proper attitude above the surface of the earth. Under normal operating conditions, the amount of water released inside the casing is usually quite small. However, when one of these prior art devices fail to deploy due to one of the previously described problems, the casing rapidly fills with water and the surrounding area can become flooded, thus causing damage to the lawn or areas adjacent thereto.
Therefore, it has long been known that it would be desirable to have an apparatus for enhancing the performance of a sprinkler assembly or the like, which operates to insure full extension and full retraction of the sprinkler assembly as intended during operation, which is adapted to a wide variety of pop-up type sprinkler assemblies, which is adapted to be constructed as an operable part of a sprinkler assembly during manufacture or retrofitted on existing sprinkler assemblies, and which is operable selectively to release fluid to the sprinkler assembly when the sprinkler assembly reaches a predetermined position above the surface of the earth.